A 400-kg box is lifted vertically upward with constant velocity by means of two cables pulling at 40.0° on either side of the vertical direction.What is the tension force that each cable exerts on the box?
A)231 N
B)400 N
C)800 N
D)2560 N
E)3920 N

Question

Quizplus · Accepted Answer

Since the box is moving with constant velocity, the net force is zero. The gravitational force on the box is 400 kg * 9.8 m/s² = 3920 N. The vertical component of the tension in each cable must add up to 3920 N. If T is the tension in each cable, then 2 * T * cos(40°) = 3920 N. Solving for T gives T = 2560 N.

A 400-Kg Box Is Lifted Vertically Upward with Constant Velocity